1. Field of the Invention
The present invention relates to a cooling circuit for a liquid-cooled internal combustion engine for motor vehicles including a control valve for controlling the flow rates.
2. Description of the Related Art
US published application US2007/0131181A1 describes a cooling circuit for an internal combustion engine, which has a main cooling circuit for the internal combustion engine and a secondary cooling circuit for a retarder as a braking device of the motor vehicle. The main cooling circuit, which has an integrated bypass line for decoupling the radiator when the internal combustion engine is still cold, is controlled by a thermostatic valve. The heat generated in the retarder in the activated state or braking mode, is dissipated via the main cooling circuit. In this arrangement, a changeover valve is integrated into the secondary cooling circuit and, by this valve, the secondary cooling circuit can be decoupled when the retarder is not activated in order to relieve the load on the delivery pump supplying both cooling circuits.
It is an object of the invention to provide a cooling circuit of the type in question which, while involving little outlay on construction, allows improved thermal design and control of the fluid flows in both circuits.